1. Field of the Disclosure
The present invention relates to organic electro-luminescence display devices, and, more particularly, to an organic electro-luminescence display device and a method for fabricating the same, which can improve reliability and reduce production cost.
2. Discussion of the Related Art
Recently, various kinds of flat display devices are under development for reducing weight and volume which is a disadvantage of cathode ray tubes. In the flat display devices, there are liquid crystal display devices LCD, field emission display devices FED, plasma display panels PDP, electro-luminescence display devices by using organic electro-luminescence display devices (organic EL display device), and so on. Active research for improving display quality and fabricating large screen sizes is ongoing.
Of the flat display devices, the organic EL display device, a spontaneous emission device, has advantages of fast response speed, high emission efficiency and luminance, and large viewing angle. The organic EL display device is provided with a thin film transistor array unit formed on a transparent substrate, an organic EL array unit on the thin film transistor array unit, and a glass cap for isolating the organic array unit from the external environment.
The thin film transistor array unit has gate lines, data lines, and driving units for driving organic EL cells, such as cell driving units.
The organic EL array unit has a matrix of organic EL cells connected to driving thin film transistors in the thin film transistor array unit.
The organic cells in the organic EL array unit are susceptible to degradation from moisture and oxygen. In order to solve such problems, an encapsulation step is performed, in which the substrate having the organic EL array unit formed thereon is bonded to the glass cap with sealant. The glass cap disperses heat generated at the time of light emission and protects the organic EL array from external forces, oxygen, and moisture in the air.
The glass cap has moisture absorbent attached to a surface facing the organic EL array unit. The moisture absorbent serves to absorb moisture and oxygen from the organic EL array unit packaged by the glass cap. The moisture absorbent is also called a getter.
However, as the organic EL display device becomes larger gradually, in cases the glass cap sags or a portion having the moisture absorbent attached thereto are pressed down by an external pressure, scratches are formed on the organic EL cells due to the moisture absorbent to cause a image defects, such as dark spots. As a result of this, reliability of the organic EL array unit is impaired.